Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
20~73~
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Fries - 31
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Submersible Machine ~-
Background of the Invention ~ ~
The invention concerns a submersible machine such as an ~ ;
electrically driven submersible mixer.
A machine of this type comprises an enclosed electric motor
which via a rotary shaft and possibly a gear box drives a
propeller which obtains mixing of the surrounding medium.
The shaft is normally supported by two ball bearings one on
each side of the rotor and is sealed on its way towards the
propeller by help of one or several seals which prevent the
~u~ul~ding medium from entering the motor along the shaft.
A mixer of this type is shown in the Swedish Design ~-
Registration 33 623.
The enclosure of the motor is normally designed with a gable
and a cylinder formed in one piece, while the gable headinq
the propeller is attached to the cylinder formed part by
screws. The enclosure must of course be so rigid that it is
able to absorb strong torque and axial forces caused by the
rotation of the propeller and its thrust. This means that
the bolted ~oint becomes relatively expensive and in
addition takes a lot of axial space.
,
Accordlng to the invention a solution has been obtained
which solves the design problem mentioned, provides
conslderable cost savings, and obtains a reduction of the
diameter of the enclosure.
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72432-66
Summary of the Invention 2 0 5 7 5 3 3
The objects and advantages of the invention will
become apparent by the present invention in which a submersible
machine has an electric motor and a hydraulic part connected by
a rotary shaft, and in which the shaft has its end turned away
from the hydraulic part resiliently supported in a stator casing
surrounding the motor.
More particularly, the invention provides in a
submersible machine comprising an enclosed electric motor have a
stator, rotor and shaft , and a propeller being mounted on one
end of said shaft, the improvement comprising: a one piece
stator housing having a cylindrical part and a gable portion;
said gable portion in its central part being formed as a cup
with an opening therethrough; said one end of said shaft being
supported by a first bearing secured to the stator housing by
means of a bearing support; another end of said shaft opposite
said one end of said shaft extending through said cup opening
and being mounted therein by a second bearing having an outer
ring and an inner ring; spring means being arranged between said
second bearing and a lock ring which is positioned within said
cup, whereby said spring means presses one side of the outer
ring of said second bearing to move said second bearing and said
shaft toward said gable; and a nut being screwed onto said other
end of sa1d shaft and into contact with the inner ring of said
second bearing to move said second bearing against the force of
said spring means a predetermined amount, such that said second
bearing and said shaft are prestressed by a dominating axial
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72432-66
force.
Brief Description of the Drawinqs
The features and objects of this invention will become
more apparent by reference to the following description taken in
conjunction with the sole drawing which shows a partial cross-
sectional view of the machine according to the invention.
Detailed Description of the Preferred Embodiment
In the drawing a rotary shaft 1 is connected to the
rotor 2 of an electric motor. The stator 3 is surrounded by a
stator housing formed by a cylindric part 4 and a gable 5. A
propeller 6 is mounted on the shaft 1, and an intermediate seal
device is mounted on the shaft behind the propeller. The
machine includes a bearing 8, a locking nut 9, spring means 10,
a lock ring 11, and a cup portion 12 is formed as part of the
gable 5. The lock ring 13, a socket 16, another lock ring 17, a
cap 18, and a seal room 19 are shown.
The mixing device according to the invention is thus
meant to operate entirely submersed in the medium to be mixed.
Sometimes the mixer must operate at very deep levels in a liquid
which means that the mixer enclosure must withstand
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very strong static presau~es. The enclosure must thus be
absolutely seal proof.
~ '
In order to provide a design which will not deform, the
stator housing, which forms the enclosure for the main part
of the driving unit, is designed as a rigid construction
preferably made of cast iron. The cylindric part 4 and the `~
gable S are manufactured as one piece, and the gable 5
supports the bearing 8.
`'
The bearing 8 which is of a type that supports axial forces
in one direction, is mounted on shaft 1 and in the central -
part of the gable 5. The central part is designed like a
cup 12. The bearing is positioned so that its outer ring is
moved behind a lock ring 13 in the cup portion 12, thus
cau~ing the cup portion to aur~uulld the outer ring with some
play. Springs, such as one or several cup springs lo, are
mounted in the cylindric part of the cup 12. The springs 10
are supported by a lock ring 11 in the cup on the side of
the bearing 8 that is further from the end of the shaft.
:',
A nut 9 is s~.~wed into the end of the shaft into contact
with the inner ring Or the bearing 8. As the nut g is
s~.w~d further inwards, the bearing will be moved against
the force of the springs 10. This .. - t continues until
the contact b~t _~l the outer ring of the bearing and the
lock ring is s~ -t relieved. In this position the
bearing 8 and the shaft 1 are floatingly supported in the
stator housing 4, 5 and p~e~t.essed by a dominating axial ,~
force. ` '
. .
The spring a..~n~ t may alternatively be arranged on the
shaft between the unit and the bearing, the shaft then being
allowed to slide axially in the inner ring of the bearing. ~- -
3 ~
.; . " . ~. . .
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According to a special arrangement, the construction is
given such resilience that the demand for springs is
eliminated.
The at~ t of the bearing support 14 for the other
bearing 15 may then be very simple as it only supports axial
1~ .
forces from the propeller and the prestressed spring ~.
These forces act in the same direction. Thus the bearing is
attached at a shoulder on the shaft 1 by help of a socket
16, which in its turn is locked on the shaft by a lock ring
17. The circumference of the bearing support 14 is sealed
against the cylindric part 4 by O-rings with no need for ~~
screws or the like.
::
The r~ ' ~nical seal 7 is connected to an area 19 adjacent
the bearing support 14 which preferably contains oil for
lubricating and cooling of the seal surfaces. The area 19
is limited by a gable cap 18 connected to the circumference
of the support 14. -
: -
~By h-lp of the invention is obtained a non exyensive and
simple design which simultaneously offers a rigid attachment
of the ins parts into the enclosure. Further advantages
are th- lack of the conventional gable h~ing the propeller
which means a more slim design. In addition the resilient
ate~ - ~ of the bearing 8 in the stator housing means that
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the ~~-~S~care pressed away from the propeller in their ~``
initial positions already. This means that there is no play
which may cause leakage when the r -^h ine starts and stops.
While I have d-scribed the principles of my invention in
connection with specific apparatus, it is to be clearly
~ ood that this description is ~ade only by way of
example and not as a limitation to the scope of the ~;~
invention as set forth in the a~ ,-nying claims.
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